1. Field of the Invention
The present invention relates to a shielding apparatus for protecting a machine, and more particularly, to a shielding apparatus fixed above the machine to protect the machine.
2. Description of the Prior Art
In general Fab, all processes are performed in a clean room. To save space, a plurality of mezzanines are adopted in the clean room whereby both a mesh anti-acid zinc-plated steel ledge and a handrail are installed at a predetermined height followed by the installation of a chief machine and a plurality of lines and tubing.
However, two design problems occur. The first problem is the inability of the mesh anti-acid zinc-plated steel ledge and the handrail to protect the machine and the people below from falling tools and debris due to the existence of an interspace between the mesh and the handrail. The second problem is the escape of acidic and basic process liquids or volatile gases used during processes in the tubing and the lines, such as the mixture of nitric acid and hydrofluoric acid to remove silicon dioxide in the wet etching process. These process liquids or volatile gases may escape from the joint of the lines and the tubing or from the machines on the mesh, and through the interspace of the mesh and the handrail to harm the machines and people below.
The high volatility and corrosiveness of the process liquids or gases can lead to severe physical damage to those they contact. As well, the process liquids or volatile gases can lead to the corrosion of the machines and electric circuits below, resulting in breakdown of the entire machine and hindering the subsequent processes of a production line. As well, within the clean room, particles volatilized from the process liquids or gases can damage the wafer surface.
Please refer to FIG. 1. FIG. 1 is a schematic diagram of the prior art. In the prior art, a shielding apparatus 100 is installed within a clean room 200. The clean room 200 comprises the shielding apparatus 100, an air filter 202, a gas inlet 204, a gas outlet 206, a mesh steel ledge 208, a machine 210a positioned atop the mesh steel ledge 208, and a machine 210b positioned below the mesh steel ledge 208. The shielding apparatus 100 comprises an anti-acid zinc plate 102 fixed above the machine 210b, and four supporting beams 104 positioned vertically at the four corners of the anti-acid zinc plate 102 (only two of 104 are shown). The anti-acid zinc plate 102 has a greater area than that of the machine 210b to allow for the protection of the people and the machine below.
The clean room 200 uses the air filter 202, the gas inlet 204, and the gas outlet 206 to maintain a proper level of cleanliness. For example, the air filter 202 removes the particles in the air, the gas inlet 204 supplies fresh air into the clean room 200 and attenuates the concentration of the particles in the air, while the gas outlet 206 expels the air out of the clean room 200 to allow for sufficient convection.
The original design of the clean room 200 is to maintain cleanliness through sufficient filtration of particles by the air filter 202 as well as maintaining sufficient convection by the gas inlet 204 and the gas outlet 206 (as shown by arrow heads). However, the location of the shielding apparatus 100 of the prior art hinders air circulation (as shown by arrow heads) and consequently, hinders the ability of the clean room to maintain a proper level of cleanliness.
Although the structure of the prior art protects the people and the machine from the formed process liquids or volatile gases as well as from falling tools and debris, it hinders air circulation and therefore affects the maintenance of a proper cleanliness level.
It is an object of the present invention to provide a shielding apparatus to solve the above mentioned-problems.
In accordance with the claimed invention, the present invention provides a shielding apparatus installed over a machine in a clean room to protect the machine. The shielding apparatus comprises at least two supporting beams and a plurality of rectangular-shaped plate flaps placed parallel to each other. The flaps are connected to the supporting beams at an angle, and each flap has areas overlapping with the neighboring flap along a vertical cross-section. The smallest length of edge area projected on the vertical cross-section is between 1 mm to 20 cm. Each flap is an anti-acid zinc-plated steel plate, and is connected to the bottom of the neighboring flap by a mesh plate. A drain piping is connected to the bottom of each flap to collect and deliver process liquids.
It is an advantage of the present invention that the shielding apparatus can efficiently solve the above-mentioned problems.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings.